1. Field of the Invention
The invention relates to a passenger-seat airbag device in which a passenger-seat airbag is inflated and deployed at the time of frontal collision, and a method of folding the passenger-seat airbag that is folded and stored in the passenger-seat airbag device.
2. Description of the Related Art
Conventionally, a passenger-seat airbag device is provided to protect an occupant seated at a passenger seat from an impact at the time of frontal collision. Japanese Patent Application Publication JP-A-2004-268903 describes an example of a passenger-seat airbag device in which a passenger-seat airbag includes a pair of left and right airbags, and a recess is formed between the left and right airbags. When the passenger-seat airbag starts to be deployed, the passenger-seat airbag receives a plurality of areas of the occupant's body, such as the shoulders. As a result, the load applied to the occupant is dispersed and reduced.
With this configuration, the airbag is ordinarily folded and stored, for example, below the top wall portion of an instrument panel. When a frontal collision occurs, the airbag opens an airbag door provided in the top wall portion of the instrument panel. Then, the airbag hits the windshield, and the airbag is deployed toward the rear of the vehicle. As a result, the airbag receives the shoulders and the like of the occupant seated at the passenger seat to absorb the impact. Accordingly, as the accuracy of the direction in which the airbag is deployed is higher, the performance of protecting the occupant is more stable.
However, in Japanese Patent Application Publication JP-A-2004-268903, the root portion of the folded airbag is positioned above the gas-injection holes of the inflator. Therefore, a gas passage through which a sufficient amount of gas flows cannot be formed above the gas-injection holes of the inflator when the airbag starts to be deployed. Thus, the gas flows into the left and right airbags, and the left and right airbags contact the windshield and the instrument panel, before the root portion of the airbag is sufficiently inflated. That is, the left and right airbags contact the windshield and the instrument panel slowly. As a result, the left and right airbags are likely to move upward or downward. This makes it difficult to stabilize the direction in which the airbag is deployed.